


Musical Code

by sadhorse



Category: Deltarune (Video Game), Undertale (Video Game)
Genre: 'Goner Kid', Bathroom, Chubby, F/F, Fat Girls, Fat fetish, Female Monster Kid, Headcanon, Short, Side Story, practice, rude humor, sibling shenanigans
Language: English
Status: In-Progress
Published: 2019-08-12
Updated: 2019-08-12
Packaged: 2020-08-20 05:27:08
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,451
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20222545
Author URL: https://archiveofourown.org/users/sadhorse/pseuds/sadhorse
Summary: Mary-Kaye Munstar, better known as Monster Kid, or MK for short, practices talking to her crush in front of a mirror.





	Musical Code

**Author's Note:**

> Okay so this is sort of me stretching my writing muscle some to work out the rust. MK here is probably going to be a supporting character to Noelle's Gift, in some way. But in any case, I think now and then I might post this side story going on parallel to the main story.
> 
> This was tricky to do, being a little rusty, but I hope it's an enjoyable read none the less.

This was her moment. This was the moment that would make or break her life. She took a breath…and spoke.

“H-Hey, Catti! What’s up?”

Mary-Kaye Munstar grinned like a moron at the reflection in her bathroom mirror. Slowly but surely, her smile melted away into a sullen look, and she blew a raspberry in frustration. “Come on, you can do better than that, MK!” She mumbled releasing a sigh before closing her eyes.

_Okay. Come on. Focus. Picture that sexy cat. Come on…just…think about those chubby white jowls…those gorgeous golden eyes…the raven black hair with the pink stripe…_ The young reptilian monster chewed at her bottom lip, feeling a tightness grow in her groin as her hormones acted on the images in her head. One of her small, still growing claws started to inch upward toward her flat chest. It only brushed across the nipple under her pajama shirt before she caught herself, gripping the bowl of the sink in front of her to gain control of her hands.

_Come on, don’t be creepy! Not time for that! Shit, focus!_ She tried again, but this time, with less…alluring imagery. She willed her hormones to behave – a monolithic task for a sixteen-year-old girl.

Finally, she opened her eyes. In the mirror staring back at her, was Catti, with a bored expression on her face. The entirety of the Munstar house bathroom melted away, as MK plunged into her fantasy realm. She trembled very gently, anxiety overtaking her, but she took a slow breath, and calmed herself. It wasn’t real. She wasn’t really Catti. This was the reason she was practicing.

Even with that realization, however, she couldn’t help but wring together her off color claws, damp with sweat. Her mind went blank as Catti messed with her phone. Her heart pumped into her chest.

“What’s up Catti?” She finally said, trying to keep her voice steady. Half lidding her eyes; she tried her best to look cool to her crush. She couldn’t let her know how into her she was, that’d be dorky! She had to be…cool and aloof. Right.

Catti’s golden eyes shifted slightly towards the lizard girl…and then back to her phone. Failure.

_Ugh…no. That’s stupid._ MK slapped her claws to her face, sliding them down across her visage in exasperation._ Come on, get your head in the game, MK! _She brought her hands up once more, rapping the sides of her skull with her knuckles to try and beat some sense into her mind.

_Okay, okay. Try again. _

“Hey, Catti you dating anyone?!” She blurted out.

Catti looked at her with widened eyes, and then squinted in disgust. MK envisioned her getting up from her desk and moving away.

Mary immediately pressed her head against the mirror with a groan. Why was this so hard?!

_It’s okay. It’s okay. Reset. Try again. _She told herself, standing up straight again.

“So…Catti. You uh…doing anything later?”

Catti looked up from her phone, and then just rolled her eyes before looking back. _Okay you’re on a good road, just tweak it a little._

“He-” The words died in her throat as another voice broke her illusion, and bathroom, her mirror image returned.

“♪Catti and Mary, sitting in a tree! K-I-S-S-I-N-G!♫” Came a taunting voice. Mary-Kaye spun around to see her little brother, Russel, standing in the doorway, hopping from foot to foot and chanting.

“H-Hey!” The elder Munstar kid scowled as her voice cracked and her face flushed a more than healthy red. “Don’t you knock, you little cretin?!”

Without skipping a beat and in typical little sibling manner, Russel called down the hallway. “Moooooom! Mary called me a Cretiiiiin!”

The authoritative voice of their mother called back. “Mary-Kaye, don’t call your brother a cretin!”

“But Mom-!” Mary began.

“No buts, young lady!”

Mary groaned, and shot her little brother a dirty look. Russel stuck out his fat headed tongue smugly in response. Mary bit her own, and then turned back to the mirror, opening the medicine cabinet for her toothbrush and toothpaste before starting to aggressively brush.

She could hear her little brother’s large, clawed feet clack against the tile bathroom floor as he moved in, hopping onto the toilet next to the sink, and plopping down. Mary looked at him from the corner of her eye, and he stared back at her, expectantly.

_Just ignore him, he’s trying to get on your nerves._ The young monster told herself, scrubbing away the remainder of her dinner diligently.

But Russel was still staring. She could feel his gaze bore into her skull. Finally, she couldn’t take it anymore.

“UGH!” Mary slammed her claws against the bowl of the sink. “What do you want, Russel?!” She growled, turning her head to face him.

Russel didn’t really seem all that intimidated, he just sat where he was, wiggling his feet. “Why do you like her?”

“…Because she’s cool.” Mary said, rinsing off her toothbrush.

“She’s fat.”

“So?!”

“You know fat people fart a lot. Do you like farts, sis?” Her brother had the most shit-eating grin in the history of monster kind.

Mary couldn’t help but blush. He…wasn’t entirely wrong. Not that she ‘liked’ them, per say. Just it wasn’t a deal breaker. “Shut up Russel.” She grumbled out. “Shouldn’t you be in bed or something?”

“…Probably.” Russel admitted, wiggling his feet back and forth with that smile still on his face.

MK sighed, rolling her eyes and turned back to her reflection. She licked at the surface of her teeth with her tongue. There was a moment of silence between the two siblings, before finally, Russel spoke, his tone far less mocking.

“…Why are you gay?”

The question hit his elder sister like a runaway train, making her turn toward him with a start. She thought for a few moments, chewing her bottom lip lightly. “I…dunno. I just…am.”

“I heard someone say that gay people have something wrong with them.”

“Ah, don’t listen to them, Russ. They’re just prejudice. Heck, when you have high school biology, you’ll see monsters can be whatever they want.” She gave him a reassuring smile, and he gave her a relieved grin back.

“So, you really gonna ask her out?!” He asked, hopping to his feet excitedly. “You should totally do like Captain Muscles! He just goes-” Russel put on his best gruff voice to imitate his hero. “‘How yah doin?’, and everybody just swoons!” He had the biggest grin on his face, like he had just given the best advice. It made Mary laugh.

“Russ, that’s just a cartoon, yo!”

“Well yeah…but I mean…he just says it with a lot of confidence! That’s what people like, right?” He nodded affirmatively. “That and muscles.”

“Yeah, that’s what people say.” She sighed. “That’s why I’m…practicing. Trying to get the confidence.” Mary turned back to her reflection, and grimaced, grabbing the sides of her paunch and giving it a bit of a shake beneath her shirt. She lifted her shirt and poked at the gut beneath. “…I could probably use the muscles too, yo.” The young woman lamented, pursing her lips.

“…Probably not.”

Mary quirked a brow and turned back to her brother. “…Say what?”

Russel hopped off the toilet and turned to his sister. “I mean…not everyone likes muscles, right? Temmie doesn’t.”

“Well, she says that.”

“Yeah yeah semantics or whatever, but point is maybe Catti doesn’t like muscle! Maybe being a ball of pudge like you is just what she’s looking for.” He grinned mischievously at his backhanded encouragement.

“…Aww you did NOT just make fun of a girl’s weight.” MK growled out. “Gonna have to punish you.” She stood there for a moment, and then moved quickly as if she was about to tackle Russel. He gasped, and ran out the room in fright, leaving the elder monster to laugh at his jumpiness.

Mary turned back to her reflection, eyeing her figure once more, removing her shirt after a few moments.

_ Well, he’s not wrong. Look at me, bottom heavy with stubby legs and a fat ass and no boobs._ She sighed, shaking her head and running a claw through the spines atop her head. “Buuut…maybe…”

Mulling it over for a few moments, the amphibian finally gave it a shot. She finger gunned her reflection, putting on her best smug expression. “How yah doin’?” She said, in her most seductive voice.

“NEEEEERD!” Russel’s voice resounded out from the doorway.

Her face flushing in both anger and embarrassment, she tossed her shirt back on as she barreled out of the bathroom after her brother. “Oh, you are so DEAD!”


End file.
